The disclosure relates to a drive apparatus mounted in a hybrid vehicle, which runs using both an engine and a motor, and a control method thereof.
Art related to a control during engine starting in a drive apparatus mounted in a hybrid vehicle, which runs using both an engine and a motor can be found, for example, in U.S. Pat. No. 6,581,705 (cols. 1-6, FIGS. 1, 2A and 2B) of the family of Japanese Patent Laid-Open Publication No. 2003-129926 (pages 1-5, FIGS. 1 and 2) described below. The art is a control art for a parallel hybrid vehicle with an engine disconnect clutch, whose purpose is to engage the engine disconnect clutch and start the engine, while also maintaining a smooth vehicle response to a driver request using the motor. In this case, the motor is controlled throughout engine starting in a speed following control mode, which performs a control adapted to however much torque is required to obtain a desired setting speed. In other words, during engine starting, the engine disconnect clutch is first engaged and then the desired speed is issued to the motor, after which fuel is supplied to the engine to start the engine. Thereafter, a control is performed that calculates the desired engine torque, and then gradually decreases the motor torque while increasing the engine torque a proportional amount. This continues until the motor torque reaches zero. The vehicle speed is maintained throughout using, for example, a proportional/integral controller.
In this case, the desired motor speed is set based upon a request from the driver and the overall vehicle operating condition. Either a trajectory or constant value therefor may be obtained based upon the acceleration and the vehicle speed at the present time and at a past point in time. On the other hand, the desired setting speed can be set to the desired engine idling speed if the driver has not instructed the present operating torque and a power transmission unit, such as an automatic transmission or the like, for transmitting driving force from the engine and the motor is not engaged.